THOUGH few remember them today, 125 years ago Robert and Gabriela Cunninghame Graham were extremely well known.

He was a strikingly handsome Scottish aristocrat and radical Liberal MP who, as a young man, had spent several years as a gaucho in South America.

His wife Gabriela was equally glamorous and moved in rackety bohemian circles.

Robert, who despaired of the poverty and wretchedness of London’s poor, infuriated his party by not only espousing increasingly hard-line Socialist ideals in Parliament, but being a shameless dandy.

He favoured wide-brimmed hats and neckerchiefs, even in London, and when he rode down Rotten Row in Hyde Park, his horse’s bridle flashed with gaudy silver medallions.

At Royal Ascot he insisted on carrying a gaucho knife under his dress suit.

His impoverished constituents in Scotland loved him just as much as his Parliamentary colleagues disapproved of him.

When he was elected, a group of 50 men met him at the railway station and insisted on uncoupling the horses and pulling his carriage from the railway station to his house.

Later, with Keir Hardie, he founded the Scottish Labour Party, precursor of the Labour Party.

Gabriela was artistic and hauntingly beautiful, with black hair and grey-blue eyes.

She was friends with the likes of Oscar Wilde, the poet W B Yeats, and Friedrich Engels, who gave her the affectionate nickname of “la Espagnola”.

The artist Will Rothenstein wrote of her “full and sensual lips”; she was, he sighed admiringly, “startle-eyed and rather shy, like a kind of squirrel”.

She loved fine clothes, food, wine and pretty jewellery.

Her poignancy was enhanced by her tragic childhood: both her father, French nobleman Francisco Jose de la Balmondière, and his elegant Spanish wife had been killed in an accident when Gabriela was just 12.

Subsequently she was taken from Chile to live with an aunt in Paris where she attended a convent school.

It was in Paris, in the Tuileries Gardens, that Robert Cunninghame Graham, riding an unruly horse, nearly knocked her off her feet.

Before he had even dismounted to apologise, he had fallen head over heels in love.

The couple were married in the Strand Register Office in London six weeks later. Gabriela was just 17.

They honeymooned in Mexico, where they slept under the stars and were ambushed by Apache Indians.

Robert and Gabriela were married for nearly 30 years.

The story of their whirlwind romance was famous among their friends who knew it off by heart; both of Robert’s first two biographers faithfully reported the romantic Parisian encounter.

The first, Tschiffley, cooed over Gabriela’s “slight accent, neither French nor Spanish, but most attractive and charming, as foreign accents sometimes can be, especially with ladies”.

The accent may well have been charming. It was also a complete fake.

Gabriela died in 1906 and Robert some 30 years later but it was not until 1985 that a trunk of forgotten papers discovered in the attic of the family home revealed the truth about her past. She was neither the Catholic child of Continental parents, nor had she been raised in Chile.

Her name was not Gabriela de la Balmondière. She had even lied about her age.

Her real name was Carrie Horsfall and she was the second daughter of Henry Horsfall, a Yorkshire surgeon from Masham, in the Yorkshire Ridings.

Little wonder, then, that her accent was hard to pin down.

Most astonishingly of all, she had continued to keep in touch with her mother secretly after her marriage, writing her letters and sending little presents for her nephews and nieces.

The reason for her deception was simple.

In one of the letters found at Gartmore, Carrie’s sister Madge wrote that “she wanted to go on the stage, which at that time was simply anathema to papa and to most other people”.

Aged 15 and determined to defy her father, Carrie ran away to London.

The first time she was brought home in disgrace. The second time she got away.

No one knows exactly what happened to her over the next three years.

Gabriela was buried at Robert’s family home, Gartmore House in Aberfoyle

Startle-eyed and rather shy, like a kind of squirrel

The artist Will Rothenstein

There is no evidence that she ever fulfilled her ambition to go on the stage.

She had no money, no means of support. In one of the discovered letters her sister Madge wrote that “somehow Mama got to know that she had been adopted by a wealthy old Spanish Don and was somewhere in the Americas”.

Adoption was almost certainly a euphemism; it is more likely she became a rich man’s mistress or perhaps even a prostitute. She could even have met her husband in a brothel.

Cunninghame Graham wrote very sympathetically about prostitutes and was described by one friend as “probably as knowledgeable a connoisseur of courtesans as horses”.

As a fierce critic of hypocrisy, we can presume he would not have held his wife’s history against her.

Other suggestions have been made for the change of name.

Grace Horsfall, the youngest of Carrie’s sisters, visited Carrie in France some years after her marriage.

The family papers indicate that something happened there that shocked the young Grace profoundly, though she never told anyone what had happened.

Perhaps Carrie’s marriage to Robert was bigamous; perhaps there was a child, though no trace of such a child exists.

Whatever the truth is, we shall never know for sure.

What the letters do reveal, however, is the constant fear of Carrie’s exposure.

According to Madge, the sisters were “not allowed to mention her name, nor let anyone know where she was nor anything”.

This fear intensified after Robert was suspended from the House of Commons for swearing and then, even more notoriously, imprisoned at Pentonville for his part in Bloody Sunday, a banned demonstration that turned into a violent brawl.

If the truth about Gabriela had been uncovered then, the scandal would have brought a decisive end to Robert’s political career and ruined both of their reputations.

Both of their families would have been disgraced.

The anxiety persisted throughout Carrie’s life and beyond.

Robert fell in love the instant he met Gabriela

When she died in France aged 48, another sister, Mary, wrote: “Of course her burial is very different to anyone else’s. I shall watch the papers for I am certain in spite of all the story will come out… What I want to find out is what name he registered her death in for then, if other than Papa’s and Mama’s, he can be charged with perjury.”

Robert brought his wife back to Scotland and buried her on the island in the middle of their lake.

Almost every fact on the death certificate he registered was false. The records state that Gabriela died at 44.

So why did the truth never come out? Theirs was not, after all, the most watertight of deceptions.

Even in an age without the internet, it would not have been difficult to establish that the aunt in Paris was an invention and from there to unravel the whole sorry tale.

As it was, it seemed that no one ever tried.

Although the tabloid newspapers as we know them today had just begun to flex their muscles in London (their revelations of adultery completely destroyed the career of the great Irish Home Ruler Charles Stewart Parnell), they never fixed upon the Cunninghame Grahams as potential targets.

As for the families involved, they had a good deal too much to lose ever to breathe a word about the true story behind Gabriela’s glamorous façade.

Such a story is, of course, irresistible to the novelist.

In Beautiful Lies, I have written my own version of Gabriela’s life, filling in the gaps with my imagination.

It is, however, not the true story nor ever could be.

Long after his wife’s death, Robert wrote that “it is a natural desire in the majority of men to keep a secret garden in their souls, a something that they do not care to talk about, still less to set down, for the other members of the herd to trample on”.

He would doubtless have been glad to know how very many secrets still remain.

Beautiful Lies by Clare Clark (£8.99; Vintage) is published in paperback on June 6.

To order your copy with free UK delivery call 01872 562311 or order online at expressbookshop.com.